Record number :
Title of article :
Experimental investigation of pneumatic soil vapor extraction
Author/Authors :
C.K. H?ier، نويسنده , , T.O. Sonnenborg، نويسنده , , K.H. Jensen، نويسنده , , C. Kortegaard، نويسنده , , M.M. Nasser، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2007
Pages :
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Abstract :
Soil Vapor Extraction (SVE) is a common remediation technique for removing volatile organic compounds from unsaturated contaminated soils. Soil heterogeneities can however cause serious limitations to the applicability of SVE due to air bypassing low permeable areas of the soil, leading to diffusion limitation of the remediation. To enhance removal from areas subject to diffusion limitation a new remediation technique, pneumatic soil vapor extraction, is proposed. In contrast to traditional SVE, in which soil vapor is extracted continuously by a vacuum pump, pneumatic SVE is based on enforcing a sequence of large pressure drops on the system to enhance the recovery from the low-permeable areas. The pneumatic SVE technique was investigated in the laboratory using TCE as a model contaminant. 2D-laboratory tank experiments were performed on homogeneous and heterogeneous sand packs. The heterogeneous packs consisted of a fine sand lens surrounded by a coarser sand matrix. As expected when using traditional SVE, the removal of TCE from the low permeable lens was extremely slow and subject to diffusion limitation. In contrast when pneumatic venting was used removal rates increased by up to 77%. The enhanced removal was hypothesized to be attributed to mixing of the contaminated air inside the lens and generation of net advective transport out of the lens due to air expansion.
Keywords :
Pneumatic soil vapor extraction , Remediation technology , TCE , unsaturated zone , Gas expansion , Venting
Journal title :
Journal of Contaminant Hydrology
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Link To Document :